diff --git a/Kanban/App/AppDelegate.swift b/Kanban/App/AppDelegate.swift
index e83b14e..618085d 100644
--- a/Kanban/App/AppDelegate.swift
+++ b/Kanban/App/AppDelegate.swift
@@ -34,6 +34,31 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
         return false
     }
 
+    /// Double-clicking a `.kanban` folder in Finder, or `open -a` — "opening a board from Finder is a
+    /// standard document open" (02-architecture.md § Launch and window lifecycle). Every URL is
+    /// forwarded to `AppModel.openBoard(at:)`, the exact entry point welcome and File ▸ Open… already
+    /// call (`AppModel.presentOpenPanel()`), so a Finder open gets the identical registry record,
+    /// board window, and recents stamp, and a board that is already open focuses its window rather
+    /// than opening a second one — `openBoard` starts its own security-scoped access on the URL, the
+    /// same as the open panel's, so nothing needs stashing here first.
+    ///
+    /// **Not pre-validated.** Info.plist's `CFBundleDocumentTypes` declares the UTI, so macOS should
+    /// never route anything but a `.kanban` folder here — but if it did, or the folder has since gone
+    /// missing, `openBoard`'s fail-fast load surfaces the failure row-level on welcome, uniform with
+    /// every other open failure. A second vocabulary for "not a board" here would just be a worse copy
+    /// of the one that already exists.
+    ///
+    /// **Can fire before any scene has appeared** — a cold launch (the app was not already running)
+    /// delivers this ahead of the first window's `onAppear`, which is where `windowOpener` is normally
+    /// captured (`CaptureOpenWindow`). `openBoard` buffers a URL that arrives that early and replays
+    /// it once the action exists, so this method does not have to reason about launch ordering itself.
+    func application(_ application: NSApplication, open urls: [URL]) {
+        guard let appModel else { return }
+        for url in urls {
+            appModel.openBoard(at: url)
+        }
+    }
+
     /// Quit runs the close flush for **every** open board before the app goes away.
     ///
     /// The same `CloseFlushCoordinator` sequence as a user close, once per board, in the same fixed
diff --git a/Kanban/App/AppModel.swift b/Kanban/App/AppModel.swift
index f823404..60be6d5 100644
--- a/Kanban/App/AppModel.swift
+++ b/Kanban/App/AppModel.swift
@@ -251,11 +251,25 @@ public final class AppModel {
     @ObservationIgnored
     public var windowDismisser: DismissWindowAction?
 
+    /// URLs handed to `openBoard(at:)` before `windowOpener` existed to open them — a cold launch's
+    /// Finder-open (`AppDelegate.application(_:open:)`) can arrive ahead of the first scene's
+    /// `onAppear`. Held in order, replayed the moment `captureWindowActions` gives the app somewhere
+    /// to open them, then discarded — the buffer is a doorway, not a second registry of intent.
+    @ObservationIgnored
+    private var pendingOpenURLs: [URL] = []
+
     /// What `CaptureOpenWindow` calls. A method rather than two assignments so the launch flow, which
     /// needs the actions before any `onAppear` has run, has one thing to call.
     func captureWindowActions(open: OpenWindowAction, dismiss: DismissWindowAction) {
         windowOpener = open
         windowDismisser = dismiss
+
+        guard !pendingOpenURLs.isEmpty else { return }
+        let urls = pendingOpenURLs
+        pendingOpenURLs.removeAll()
+        for url in urls {
+            openBoard(at: url)
+        }
     }
 
     // MARK: Recents
@@ -403,9 +417,13 @@ public final class AppModel {
     ///
     /// Security-scoped access starts here, *before* the window exists, because the host's very first
     /// act is a tree walk: a scope started after the load would be too late.
+    ///
+    /// **Called before any scene has appeared, and that's fine.** A cold launch's Finder-open can
+    /// reach here before `windowOpener` is captured; the URL joins `pendingOpenURLs` and this same
+    /// method runs again for it once `captureWindowActions` has something to open it with.
     public func openBoard(at url: URL) {
         guard let windowOpener else {
-            Self.logger.error("openBoard with no window opener captured yet — ignored")
+            pendingOpenURLs.append(url)
             return
         }